A known sliding screen assembly includes a frame which is fitted to an exterior of an existing window. The frame houses a mesh screen which is attached to a pull bar arranged to move between open and closed positions. In the open position, the screen is concertinaed against one side of the frame to provide free access through an opening defined by the frame. In the closed position, the screen is fully extended across the opening.
The pull bar and screen travel on a series of guide wires which provide support and degree of rigidity to the screen and pull bar. The guide wires are fixed to the concertinaed screen side of the frame, follow spaced apart parallel paths through the screen, are diverted through holes in the pull bar to opposite ends of the pull bar and then tied to the opposite side of the frame.
The guide wires run adjacent the frame, between the pull bar and associated tie points, so as not to obstruct the opening when the pull bar is in the open position.
Frictional loads generated by the wires passing through the pull bar, as it is moved between the open and closed positions, render this assembly design suitable for small scale use only such as, for example, use in association with a conventional house window. The method of tying off the guide wires can also be problematic as the tie points need to be close to the side of the frame in order to provide free passage of the pull bar into the closed position, and manual tying can be difficult in the limited space available. Also, manual tying of the wires may lead to inappropriate tensioning of some of the wires, which can restrict smooth travel of the pull bar or cause the pull bar to be skew.